Charged 2026

Tag: crime

  • Issues with the use of DNA Evidence in Criminal Cases

     

    Timothy Durham was convicted of rape when a test showed his DNA genotype matched the DNA recovered from a crime scene. Eye witnesses testified that Durham was in a different state at the time of the incident, but he wasn’t exonerated from his 3000 year sentence until follow up DNA analysis showed that the preliminary forensic analysis used in the trial was misinterpreted (Thomas et al.). DNA testing serves an invaluable part in our criminal justice system, but it comes with complications and bias that can lead to wrongful convictions and misinformed juries.

     

    Background:

    Blood testing:

    Forensic genetics aims to identify the origin of a biological sample. Forensic testing started when Karl Landsteiner discovered human ABO blood groups. With blood groups, elimination of suspects based on their blood type became possible. For example, if a suspect had type A blood, but type B blood was left at the scene by the perpetrator, then the investigators could rule out the suspect. Unfortunately, the reverse is less helpful. If the suspect and perpetrator both had the same blood type, investigators couldn’t concluded the guilt of the suspect. Blood identifiers later evolved into 8 distinct categories which improved the ability to eliminate suspects but still couldn’t conclusively identify a suspect (Jobling and Gill).

    DNA Testing:

    The field evolved in the 1980s with the discovery of Minisatellites, lines of repetitive DNA. Minisatellite patterns in DNA create what we know today as the DNA fingerprint. The DNA fingerprint can specifically pinpoint individuals with a higher accuracy rate than previous methods (Augustyn et al.). Around the same time, scientists discovered a breakthrough for victims of sexual assault. Bodily fluids of both the victim and the assaulter can mix during an attack. A new process called differential lysis could selectively increase the concentration of sperm in a fluid sample thereby allowing for accurate DNA testing (Jobling and Gill).

    Forensics evolved to use single-locus probe testing after several years because of its ease of interpretation. It looked at specific minisatellites that had high variability between subjects. This method became the first DNA-based method used in a criminal investigation. The first case used minisatellite patterns to link two murder homicides from several years apart. The DNA evidence then exonerated an innocent man, and implicated the guilty party when he tried to evade DNA testing. His guilt became reinforced when his DNA profiles matched the murderers, and he gave a full confession (Jobling and Gill).

    Finding DNA at a crime scene can’t guarantee that you’ll find a murderer. Issues with non-pure samples and limited samples make DNA work difficult, and accreditation of facilities and new techniques can take time (Jobling and Gill).

     

    Subjectivity of DNA Interpretation:

    Subjectivity might influence lab based forensics in complex cases. For example, not all DNA found at a crime scene comes from a single individual. The sample could include a mixture of several individual’s DNA. A study published in 2011 looked specifically at this issue (Dror and Hampikian).

    The Case:

    After a gang rape in Georgia, investigators used a mixture of DNA to prosecute one suspect after another suspect took a plea bargain to testify against him. Forensic scientists can look at DNA mixtures and conclude one of the following: suspect excluded, suspect cannot be excluded, and inconclusive. If the suspect is excluded, it means that there’s little possibility that their DNA is part of the sample. If the suspect cannot be excluded, it means that there’s a possibility that their DNA is part of the sample. In the trial, the DNA examiners who knew the context of the case concluded that the suspect being prosecuted could not be excluded from the DNA mixture. To the jury, this meant that the forensic examiners concluded the suspects DNA matched DNA in the sample (Dror and Hampikian).

    The Study:

    The 2011 study gave DNA evidence from this case, including DNA profiles of the suspects, to 17 forensic examiners. These examiners had no context of the case, and they worked independently. Of the 17, only 1 came to the same conclusion as the original examiners who knew the context of the case. Twelve of the 17 concluded that the prosecuted and convicted suspect had no relation to the DNA found in the sample, and the remaining 4 deemed the test inconclusive. This not only shows that subjectivity occurs due to the context of the case, but the 17 examiners had three different conclusions based on their past experiences. This proves that not all DNA analysis is objective (Dror and Hampikian).

    Some organizations like the Scientific Working Group on DNA Analysis Methods say that quantitative statistical evidence should be presented with every categorical conclusion, but this isn’t currently required by the US (Dror and Hampikian).

    False Positives:

    There are two categories that cause wrongful identification in a DNA report: coincidental matches and false positives. Coincidental matches are DNA matches between two unrelated people. The probability of these matches is about 1 to 500,000 for white individuals and about 1 to 350,000 for black individuals. This small probability of coincidental matches makes people feel confident in DNA evidence.

    False positives, on the other hand, are matches between sample DNA and test DNA that result from issues in the forensics lab. In multiple cases forensic labs have accidentally switched victim and suspected rapist’s DNA leading to wrongful convictions. For other cases, forensic scientists misread or misunderstand a sample. In a case from 1993, a man became wrongly convicted of rape after someone interpreted a mixed sample of victim and perpetrator DNA as an individual sample. To prevent false convictions, retesting DNA is allowed, but it’s not an efficient solution. Many people are pushing for statistical information on the probability of false positives, so jurors can make accurate judgements based on DNA evidence (Thomas et al.).

     

    Conclusion:

    DNA analysis is a useful tool for the criminal justice system, but possible subjectivity raises issues in forensic testing. To combat wrongful convictions, organizations like The Innocence Project use DNA testing to free the innocent (“Help us put an end to wrongful convictions!”). But, forensic testing standards need reformation in order to prevent subjectivity and to ensure proper education of juries.

     

    Citation:

    Augustyn , Adam, et al. “DNA Finerprinting.” Encyclopedia Britannica , 26 Apr. 2018, www.britannica.com/science/DNA-fingerprinting#ref153186.

    Dror, Itiel E., and Greg Hampikian. “Subjectivity and Bias in Forensic DNA Mixture Interpretation.” Science & Justice, vol. 51, no. 4, 2011, pp. 204–208., doi:10.1016/j.scijus.2011.08.004.

    “Help Us Put an End to Wrongful Convictions!” Innocence Project, www.innocenceproject.org/.

    Jobling, Mark A., and Peter Gill. “Encoded Evidence: DNA in Forensic Analysis.” Nature Reviews: Genetics, vol. 5, no. 10, Oct. 2004, pp. 739–751., doi:10.1038/nrg1455.

    Thompson, William C, et al. “How the Probability of a False Positive Affects the Value of DNA Evidence.” Journal of Forensic Sciences, vol. 48, no. 1, Jan. 2003, pp. 1–8., doi:10.1520/jfs2001171.

     

  • Face the Trauma

    Post-traumatic stress disorder, so-called PTSD, is a psychiatric disorder that can occur in people who have experienced or endeavored a traumatic event. Commonly we heard many violent tragedies happened because of the criminals’ former unpleasant experiences, for example, rape or any personal assault.

    The pathological environment of abuse fosters the development of a post-traumatic disorder. Past experience of abuse, especially in childhood, appears to be a major factor of becoming a psychiatric patient. Those survivors came back to normal life with a large number and variety of complaints. Bryer, studying psychiatric disorder, reported that women with historical physical abuse have significantly higher scores of depressions, stress, sensitivity, etc. (Bryer, 1987) Moreover, Briere reported that survivors of childhood abuse suffer significantly more in insomnia, drug addiction, alcoholism and so on. (Briere, 1988) Herman concluded that the symptoms can be categorized into somatic, dissociative and affective sequelae of prolonged trauma. (Herman, 1922)

    https://www.betterhelp.com/advice/ptsd/possible-signs-of-ptsd-why-do-i-avoid/

    For PTSD treatment, the very first step is to access personal symptoms. The psychometric properties of the PTSD checklist (PCL), a brief and self-reported instrument, were on research based on 40 motorcycle accident victims and sexual assault victims. All the participants need to complete the PCL and take the interview as feedback. For the PCL the PTSD symptoms are evaluated on a scale indicating how much had the respondents been bothered by a particular symptom from 1 to 5. The results supported the value of PCL as an accessing device for the possible presence of PTSD. (Blanchard, 1996)

    https://www.verywellmind.com/thmb/SbtJky-uv56Z2DdkNtlgtdPAknE=/1500×0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/ptsd-treatment-2797659_FINAL-5c12be374cedfd00010f866a.png

    Prolonged exposure is an effective treatment for post-traumatic stress disorder, no matter what type of trauma the patients endeavored. The PE therapy includes four main components: psychoeducation, in vivo exposure, imaginal exposure and emotional processing. (Rauch, 2012) Psychoeducation focuses on the PTSD symptoms and the former experience. Confronting trauma-related memories can actually reduce post-traumatic disorder. In vivo exposure means confronting trauma-related environment, including people and places as a reminder. Then during imaginal exposure, patients will go through the memory with all the thoughts, emotions and trauma he or she experienced. Finally, emotional processing includes the therapist moving through an open-ended discussion of trauma and thoughts, comparing with the past.

    To be honest, PTSD happens to everyone, from small effect to tremendous causes. Some aspersion can make me self-abased, especially trauma in childhood. While facing those symptoms, just be confident and optimistic to access the level, and take a trauma-related prolonged exposure. It is a golden therapy.

     

    Bryer, J. B., Nelson. B. A., Miller, J. B., and Krol. P. A. (1987). Childhood sexual and physical abuse as factors in adult psychiatric illness. Am. 1. Psychiafry 144: 1426-1430.

    Briere, J. (1988). Long-term clinical correlates of childhood sexual victimization. AnnaL New York Acad Sci 528: 327-334.

    Herman, J. L. (1992). Complex PTSD: A syndrome in survivors of prolonged and repeated trauma. Journal of traumatic stress, 5(3), 377-391.

    Blanchard, E. B., Jones-Alexander, J., Buckley, T. C., & Forneris, C. A. (1996). Psychometric properties of the PTSD Checklist (PCL). Behaviour research and therapy, 34(8), 669-673.

    Rauch, S. A., Eftekhari, A., & Ruzek, J. I. (2012). Review of exposure therapy: a gold standard for PTSD treatment. Journal of rehabilitation research and development, 49(5), 679-688.

  • Detect True Feelings

    After watching the drama series, ‘Lie to Me’, I got curious about facial micro-expressions. Facial micro-expressions are rapidly involuntary facial expressions which reveal disguised feelings. They can be significant for understanding humans’ deceitful behaviors.

    Micro-expressions were first found by Haggard and Issacs in 1966. (Haggard, 1966) They examined the video taken of a patient, who lied to her doctor to conceal her plan to commit suicide. She pretended to be happy in the video but indeed, when cautiously checking frame by frame, they detected a concealed facial look of anguish within 1/12 second. Generally, these so-called micro-expressions happen rapidly (1/3 to 1/25 second) so that researchers need to examine the process extremely carefully. (Ekman, 2003)

    In analyzing facial expressions, the main focus is basically to detect the six basic emotions and hence to provide facial expression unit being labeled. Different people have their own unique facial expression for each emotion. As a result, researchers have been asked to first give ordinary questions about testers’ daily life to get a baseline of different emotions (not limited to six basic emotions). (Pfister, 2011) For instance, in research done at the University of Oxford, they asked a participant about his attitude toward the murderer and he appeared to be angry since his eyebrows got down and together and his eyes glared.

    micro-expression of anger

    Then changing to the question about cheating, he gave that similar facial expression as feedback. Researchers concluded that they can superficially assess that the participant never been engaged in cheating before since he should return a facial reaction of fear if he did so. (Li 2013)

    micro-expression of fear

    Compared with previously gathered micro-expression criteria, experts can better decide if the participant deceived or not.

    The field of micro-expressions is interesting in psychological research. Experts can get clues about whether someone has committed a crime. Moreover, police can quickly figure out whether the suspects deceive or not. Detecting true feelings can make life much easier.

    Pfister, T., Li, X., Zhao, G., & Pietikäinen, M. (2011, November). Recognising spontaneous facial micro-expressions. 2011 international conference on computer vision (pp. 1449-1456). IEEE.

    Haggard and K. Isaacs, “Micromomentary facial expressions as indicators of ego mechanisms in psychotherapy,” Methods of research in psychotherapy. New York: Appleton-Century-Crofts, pp. 154–165, 1966

    Ekman, P. (2003). Darwin, deception, and facial expression. Annals of the New York Academy of Sciences, 1000(1), 205-221.

    Li, X., Pfister, T., Huang, X., Zhao, G., & Pietikäinen, M. (2013, April). A spontaneous micro-expression database: Inducement, collection and baseline. In 2013 10th IEEE International Conference and Workshops on Automatic Face and Gesture Recognition (FG) (pp. 1-6). IEEE.